Joint for carbon electrodes.



No. 863,674 PATENTED AUG. 20, 1907'.

' F31". TQONE.

JOINT FOR CARBON ELECTRODES. APPLICATION FILED SEPT. 25. I906.

WITNESSES INVENTOR UNITEI D LS TATE S P ENT OFFICE.

FRANK J. TONE, OF NIAGARA FALLS, NEW YORK.

:Tom'r: son CARBON ELECTRODES:

Application as $eptember 25,1906. Serial No. 336,119.

Specification of Letters Patent.

Patented Aug-. 20, 1907.

-of this specification, which shows a carbon electrode jointed according to my invention.

This invention relates to carbon electrodes such as are used in electric fiirnaces,and hasfor its object to provide a'joint whereby two electrodes can be joined together end to end with high conductivity and good mechanical strength. Before graphitized carbons came into use it' was difficult to'join two carbons on account of the difficulty of machining them and of making a close fitting joint. In the use of graphitized car- .bons it has become customary, when it is desired to assemble two or more pieces, to thread one piece into another. In'this'way a new electrode can be joined to the end of one in use, and thus electrodes can be fed into the furnace one after another without interrupthrown away.

Several modes of making threaded joints for electrodes are in use, but so far as I am aware they have been defective in that the joints produced are weak mechanically or are of impaired electrical conductivityor of inconvenient form, and all of them have the great objection that the contact surface is not equally distributed, and in case of heating at the surface of contact, such as may be expected to a greater or less degree in all joints, such heating will be unequal and will tend to break the red. I have discovered that by connecting the parts of the electrode with a tapered threaded joint, such as shown in the accompanying drawing, the defects herein before described are entirely overcome for I not only obtain mechanically the strongest possible joint without increasing the cross-section of the electrode at the joint, but I also secure the maximum amount of contact surface and the most uniform distribution of contact surface normal to the line of'current flow; that is to say, every unit of section has an equal amount of contact surface, and the joint being equal in resistance in all its parts reduces. the effects of overheating.

In the drawing which shows the joint in its preferred form, 2, 3 are the carbon electrode pieces to be joined. These pieces are formed at the ends with a tapered threaded portion and a threaded tapered socket re 1. A joint for carbon electrodes consisting of two carbon electrode pieces having respectively'a tapered threaded end and a-t'apered threaded socket, the tapered treaded spectively, a'ndare united by securing them together.

V portions constituting substantially the entire contact surface of the joint.

2 A joint for carbon electrodes consisting of two carban electrode pieceshaving respectively a tapered threaded end and atapered threaded socket, said parts being screwed together and the tapered threadedportions constituting substantially theentiie Contact surface of the joint.

In testimony whereof, I have hereunto set my hand.

. FRANK J. TONE.

Witnesses:

ASHMEAD G. Rononns, ARTHUR BATTS. 

